As known, the solid state laser structures emit luminous energy from zones having side dimensions on the order of a few micrometers.
In order to obtain low laser threshold currents, high optical power emitted and hence maximum electro-to-optical conversion yield, it is necessary to make the current flow in the very small active zone only.
Various methods have been developed to confine the electric energy flow in the region of light emission, having as their object the maximization of the conversion yield.
For instance U.S. Pat. No. 5,151,914 discloses a device having a region blocking the current flow by means of a high resistivity layer obtained through implantation of transition (metallic) element ions. With this structure good results are obtained but the process is somewhat critical.
In an article by G. A. Vawter et al entitled "Implanted Planar Buried Heterostructure, Graded-Index, Separate Confinement Heterostructure Laser in GaAs/AlGaAs", IEEE 1989, it a laser structure is described with only one epitaxial growth and with the doping of the layers forming the region which blocks the current flow which is carried out through high energy ion implantation.
This structure has the drawback due to a low accuracy in the relative positioning between the active element and the blocking structure.